Renewable energy systems, such as utility-scale solar tracker arrays, must be constructed so as to resist strong winds and other environmental loads. The load capacity of a solar tracker array depends on, among other factors, ground conditions at the installation site, support pile height, pile construction, pile depth, and the use of filler material surrounding the pile. The lower the structure, the better wind resistance it achieves. Lower structures also permit the use of smaller solar tracker components that are less expensive to install and maintain.
Support piles are installed by using a pile driver to drive the piles to a predetermined embedment depth. Variations in ground conditions at the installation site can create challenging conditions for pile installation. To illustrate, the ground may be composed of a soft soil layer covering rock strata of varying depths, density, hardness, and materials, including, for instance, clay, shale, caliche, sandstone, granite, and limestone. Pile refusal may be encountered during pile driving if the pile is being driven through ground materials of particular hardness.
With traditional methods of pile installation, when a pile is refused, it must be extracted from the ground so that a borehole can be drilled to receive the support pile. The pile is installed in the borehole, and the borehole is backfilled with filler material. This increases the installation time and leads to undesirable cost over runs and construction delays. It would, therefore, be advantageous to provide a method for installing piles that does not require extraction in the event of pile refusal.
Accordingly, it is an object of the present invention to provide methods for installing a support pile without extraction that utilizes side drilling to break up refusal materials and to create a void for compaction of the refusal materials during subsequent pile driving.